The GEDCOM standard has defined the format of dates to allow this information to be passed between Family History Software programs or Analysis Tools like FTAnalyzer.

Even though there is a standard, most FHS allow users to add any date format they want to. This might make sense to the users as they enter the dates but makes it very difficult if you ever need to transfer your tree to another FHS or to use Analysis
Tools like FTA.

Here is a list of the date formats from the GEDCOM Specification. All formats in blue are the preferred option and should be used
before creating a non standard format.

In the following examples DATE can be in any of the following formats

1885

Year only

APR

1889

Month and Year

22

NOV

1873

Day, Month and Year

To build up a range of dates, the following are used

BEF

DATE

Event happened before the given date

AFT

DATE

Event happened after the given date

BET

DATE

AND

DATE

Event happened some time between date 1 AND date 2

FROM

DATE

Indicates the beginning of a happening or state

TO

DATE

Indicates the ending of a happening or state

FROM

DATE

TO

DATE

Indicates the beginning and ending of a happening or state

Because FHS programs don’t enforce users to adhere to the GEDCOM standards, FTAnalyzer can detect and interpret the following date format variations.